The flight instructor of the tailwheel equipped airplane reported that, during a touch and go takeoff from a grass strip, with the pilot receiving instruction on controls, the airplane veered ­­­left and the tail came up. The instructor applied right rudder, but the airplane nosed over. The airplane sustained substantial damage to the rudder. The flight instructor reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. An automated weather observation station located 9 nautical miles away from the accident airport reported that, about the time of the accident, the wind was from 200° at 12 knots, gusting up to 18 knots. The flight instructor reported that the wind, about the time of the accident, was shifting from the west to southwest about 8 to 12 knots, gusting up to 12 knots. The airplane landed on runway 14.